1. Field of the Invention
The present invention relates to a light source device, projection apparatus, and projection method suitable for a projector apparatus or the like.
2. Description of the Related Art
For example, in Pat. Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 2004-341105), in a projection display apparatus, in order to carry out color display, a surface light source emitting primary-color light of each of red, green, and blue, and spatial light modulator corresponding thereto are required, and hence the number of pieces of components are increased, and downsizing, weight saving, and price reduction of the overall apparatus cannot be achieved. Thus, technique in which a light-emitting diode emitting ultraviolet is used as a light source, a visible light reflection film having characteristics of transmitting ultraviolet light, and reflecting visible light is formed on a surface of a color wheel irradiated with ultraviolet light from the light-emitting diode, and a fluorescent substance layer emitting visible light corresponding each of red, green, and blue by ultraviolet light irradiation is formed on the back surface side of the color wheel is contrived.
However, including the technique described in above Pat. Document, conventional techniques have problems. FIGS. 5A and 5B exemplify a change in color of light emitted from the light source side of a case where a single light source and color wheel are used. FIG. 5A shows the configuration of a color wheel 1 constituted of color filters 1R, 1G, and 1B of red, green, and blue in each of which a central angle is set at 120°. The rotational position of the color wheel to be inserted in the light path from the light source is indicated by an angle from 0 to 360° of the rotational phase corresponding to the image frame.
In this color wheel 1, as shown in FIG. 5A, the color filter 1B of blue, color filter 1R of red, and color filter 1G of green are arranged in the order mentioned in the light path from the light source. FIG. 5B shows the color of the light-source light applied to the micromirror element configured to display an image, and color of the light-source light exiting from the color wheel 1.
As shown in FIG. 5B, a single light source is used to select light transmitted through each color filter, the selected light is applied to the micromirror element, and a light figure is formed by the reflected light of the micromirror element. For that reason, the color of the light-source light applied to the micromirror element, and color of the light-source light exiting from the color wheel 1 coincide with each other.
As shown in FIG. 5A, in the color wheel 1, the central angle of each of the color filters 1B, 1R, and 1G is fixedly constituted, and hence it is physically impossible to vary the width of each of the blue, red, and green field periods in the period of 360° in which the color wheel 1 rotates.
Accordingly, there has been the problem that it is not possible to cope with, for example, a change or the like in the transmission wavelength band characteristics of the color filter due to aged deterioration, or deal with the statuses of use desired by various users such as a case where adjustment of color balance is required, case where emphasis on the brightness of the image is more desired than the color reproducibility, and the like.